Linked Life Data

2159489

Source:http://linkedlifedata.com/resource/pubmed/id/2159489

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1990-6-13
pubmed:abstractText
Pulses of some Ca2+ channel blockers (dantrolene, Co2+, nifedipine) and calmodulin inhibitors (chlorpromazine) lead to medium (maximally 5-9 h) phase shifts of the circadian conidiation rhythm of Neurospora crassa. Pulses of high Ca2+, or of low Ca2+, a Ca2+ ionophore (A23187) together with Ca2+, and other Ca2+ channel blockers (La3+, diltiazem), however, caused only minor phase shifts. The effect of these substances (A 23187) and of different temperatures on the Ca2+ release from isolated vacuoles was analyzed by using the fluorescent dye Fura-2. A 23187 and higher temperatures increased the release drastically, whereas dantrolene decreased the permeation of Ca2+ (Cornelius et al., 1989). Pulses of 8-PCTP-cAMP, IBMX and of the cAMP antagonist RP-cAMPS, also caused medium (maximally 6-9 h) phase shifts of the conidiation rhythm. The phase response curve of the agonist was almost 180 degrees out of phase with the antagonist PRC. In spite of some variability in the PRCs of these series of experiments all showed maximal shifts during ct 0-12. The variability of the response may be due to circadian changes in the activity of phosphodiesterases: After adding cAMP to mycelial extracts HPLC analysis of cAMP metabolites showed significant differences during a circadian period with a maximum at ct 0. Protein phosphorylation was tested mainly in an in vitro phosphorylation system (with 35S-thio gamma-ATP). The results showed circadian rhythmic changes predominantly in proteins of 47/48 kDa. Substances and treatments causing phase-shifts of the conidiation rhythm also caused changes in the phosphorylation of these proteins: an increase was observed when Ca2+ or cAMP were added, whereas a decrease occurred upon addition of a calmodulin inhibitor (TFP) or pretreatment of the mycelia with higher (42 degrees C) temperatures. Altogether, the results indicate that Ca2(+)-calmodulin-dependent and cAMP-dependent processes play an important, but perhaps not essential, role in the clock mechanism of Neurospora. Ca2+ calmodulin and the phosphorylation state of the 47/48-kDa proteins may have controlling or essential functions for this mechanism.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0174-1578
pubmed:author
pubmed:issnType
Print
pubmed:volume
159
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
695-706
pubmed:dateRevised
2009-6-8
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
On the role of Ca2(+)-calmodulin-dependent and cAMP-dependent protein phosphorylation in the circadian rhythm of Neurospora crassa.
pubmed:affiliation
Department of Biology, University of Bremen, Federal Republic of Germany.
pubmed:publicationType
Journal Article